Increased luminous efficacy of LEDs and advancements in LED optical systems have made LED light sources a sensible choice for providing general illumination for outdoor areas such as streets, pathways, plazas and parking lots, and for large covered areas such as parking structures, underpasses and transit platforms. While LEDs generate less heat than incandescent light sources, the heat generated in “high power” LED luminaires can be substantial and must be dissipated in order to keep the LEDs cool enough so that they operate within a desired efficiency range, do not degrade and do not fail prematurely.
Heat dissipation usually is by conduction from the LEDs to a heat sink having heat dissipating elements, such as cooling fins. Vertically oriented cooling fins atop a luminaire housing enhance heat dissipation, but the spaces between the cooling fins tend to accumulate dirt and debris, as well as ice and snow during winter in colder climates. Such accumulations can reduce the heat dissipating efficiency of the cooling fins, potentially reducing LED efficiency and longevity. Placing screening or perforated sheet metal over the cooling fins in an effort to minimize or prevent such accumulations can be counterproductive because such coverings can reduce the heat dissipating efficiency of the cooling fins. Top-mounted cooling fins also preclude flush mounting of the luminaire to an overhead support surface, such as a ceiling.
Servicing of many existing luminaire designs, such as replacing LEDs, optical components or electrical components, can be rather cumbersome and/or time-consuming. This activity typically involves dismounting the entire luminaire, removing it to a workbench for servicing and then reinstalling it, or spending substantial time on a ladder or other elevated work platform disassembling the luminaire, replacing parts and reassembling the unit, all in situ.